INVESTIGATIONS OF ACID ORGANISMS OF MILK. Oe 
were found, and when fully ripened about 150,000,000 organ- 
isms per cc. Among these bacteria were found large numbers 
of B. actdi lactict (I. and B. lactis aerogenes, with a quantity of 
miscellaneous bacteria, but no single colony of B. acidi lactict 
was detected. 
Experiment No. 3.—This experiment was conducted pre- 
cisely as the last and designed as a confirmatory test. The 
results were identically the same so far as concerns the variety 
of bacteria. From these two experiments it was evident that 
when sufficient care was taken in drawing the milk in sterile 
vessels milk could be obtained which was free from the presence 
of BL. acid lactict, although it was more difficult to exclude the 
other two species of lactic bacteria. 
Lixperiments Nos. 4, 5, and 6.—In these experiments the 
attempt was made to determine whether the acid organisms 
were present in the dirt and dust which fell from the cows into 
the milk pail during the milking. Milk was drawn into sterile 
tubes and also into a sterile jar as in the preceding experiments, 
but in addition gelatin plates were exposed for different lengths 
of time under the body of the animal so as to catch some of the 
dust and dirt which fall during the milking. The results ob- 
tained with the sterile tubes and the jar of milk were practi- 
cally identical with those of the preceding experiments. A 
study of the gelatin plates gave the following results: 
‘Gelatin plates ro cm. diameter exposed under the cow tn the stall, 


NUMBER OF COLONIES ON PLATE. 

TIME OF EXPOSURE. 
In Experiment | In Experiment 
No. 


No. 4. 
IO seconds, - - - - 2 C 380 52 
20 seconds, - - - - - - 382 _ 100 
30 seconds, - - - - - - 1,736 195 
4o seconds, 2 - - - - - 3,204 500 


A study of the species of bacteria found on these plates 
showed the presence of B&B. acidi lactict (7, and B. lactis aerogenes, 
together with large numbers of miscellaneous bacteria. How- 
ever, no &. aczdz lactict were found. It was thus shown that 
two of the common lactic bacteria were found in the dust and 
